HD3SS3220: VDD5 current consumption

1: if a device plugged into DFP port,  3220 in active mode , current should be increae.

2: 100uf cap is for Vconn which supports active cable.

Best

Brian

Hi Brain,

1. you mean increase to 0.7mA ?

was this 0.7mA measured under active cable plugged or not?

2. why does Vconn needs that large capacitor for active cable?

1: when mux is on, current is increased to 0.7ma.

2: active cable has IC inside , it may draw large current.

Best

Brian

Hi Brian,

so my question is , is that 0.7mA measure in active cable or not.

since normal cable, we don't sink Vconn from VDD5,

please help answer this one, thanks

0.7ma is not directly  from active cable, it's from Mux inside .

Best

Brian

Hi Brian,

I mean this 0.7mA doesn't include active cable loss , right?

  the pull down Ra loss.  can you confirm this?

correct.

Hi Brian,

so our datasheet current consumption doesn't cover active cable loss scenario inside at all? 

you may right, but 5v/200k=0.025ma, not too much compare to  0.7ma.

Regards

Brian

hi Brian,

I’m confused what you meant,

Ra is 1kohm, 5V/1k=5mA.

so clearly it doesn’t cover active cable since the current now is only 0.7mA<5mA.

am I right?

There is 200k pullup on Vconn pin.

Best

Brian

if we can internal limited 200K  , then why do we still have to worry about large current sink from active cable?

Vconn is pulled up with external 200k to 5v.

Hi Brian

i’m confused I didn’t see any external 200W ohm at VDD5?

why you keep saying there’s 200kohm?

I think you mistaken for the Vconn_fault pin which is not a supply pin…..

sorry, I'm confused with Vconn supply and Vconn_fault which has 200k  external pullup. let me check with system.

Regards

brian

Afterr confirmed with our  system , the current 0.7ma did not include Vconn, it will be higher as you mentioned.

Best

Brian

1. so do we really need that as large as 100uF?

2. should we place it as close as possible to the mux or close to 5V DC/DC is fine as well?